• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.614-615
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• 2006

Investigation of influence the morphology of initial powder particles, application pore-formers for sintering of nickel powders and application of flux for sintering of aluminum was made. Using different methods was prepared material with size of porous in wide range size of pores ($1-500{\mu}m$). Using the flux for gravity sintering of aluminum in air atmosphere was manufactured porous material with porosity about 45%..

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.431-436
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• 2008

T-burner tests of an Al/HTPB propellant in conjunction with a Pulsed DB/AB Method were conducted to find an acoustic amplification factor. Aluminum-free and aluminum-heavy propellants were examined. Instant surface ignition was successfully made by the use of a supplementary propellant of fractionally higher reaction rate. With the presence of higher aluminum concentration in the propellants, the pressure perturbations were promptly damped down and the pressure fluctuations were no longer dispersive. Addition of aluminum particles into the propellant was advantageous for stabilizing pressure-coupled unstable waves.

• 한국분말재료학회지
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• 제25권2호
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• pp.99-103
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• 2018

Spherical monosized pure aluminum (Al) particles are successfully fabricated by the pulsated orifice ejection method (POEM). The surface reaction between Al and the graphite crucible is investigated by analysing the microstructure and chemical composition of the materials. No significant chemical reaction occurs between Al and the graphite owing to the crystalline Al oxide (${\gamma}-Al_2O_3$) layer generated in the initial state. The ${\gamma}-Al_2O_3$ layer is clearly observed in all regions between the Al particles and graphite via transmission electron microscopy and confirmed by the selected area diffraction pattern. The morphology of the ${\gamma}-Al_2O_3$ layer perfectly follows the surface morphology of the graphite crucible, which showed nanoscale roughness. This implies that molten Al could not directly contact graphite even though the surface of the crucible became rough to some extent. However, this passivation phenomenon allowed the successful fabrication of monosized pure Al particles. Therefore, POEM is a useful process at least to manufacture monosized pure Al particles.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.971-974
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• 2011

Aluminum matrix composites reinforced with SiC particles(AMC) are one of the candidate materials for the weight reduction of rolling stock brake discs. It is known that weight reduction of about 40% is possible when they replace conventional cast iron brake discs. But casting is not easy because of bad wettability of SiC with Al alloy. We developed two AMC brake discs with SiC volume fraction of 20% by a new casting method. It was found the developed method produced brake discs of good quality.

• 한국추진공학회지
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• 제22권2호
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• pp.11-19
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• 2018

본 연구에서는 하이브리드 로켓용 파라핀/알루미늄 연료의 유변학적 특성 파악을 위한 점도 측정을 수행하였다. 혼합된 알루미늄 입자의 크기와 첨가량에 따른 유변학적 특성을 파악하기 위해 평균 입도 100 nm, $8{\mu}m$의 나노 및 마이크로 크기 알루미늄 입자첨가 시료를 제작하였으며, 회전형 레오미터를 사용해 점도를 측정하였다. 나노 및 마이크로 입자 함유비에 따른 증가율 패턴은 대단히 상이하였으며 입자의 함유비 10 wt%를 경계로 점도 증가율이 구분되었고, 나노입자 첨가 시 연료의 유입 후퇴율 감소에 따른 총 후퇴율의 저하를 예상할 수 있었다.

• 한국결정성장학회지
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• 제5권4호
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• pp.351-357
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• 1995

$CF_4$ 플라즈마 분위기에서 반응성 이온식각된 알루미늄의 표면을 XPS 분석하였다. 알루미늄의 표면에$AlF_3$가 형성되었으며 표면에서의 깊이가 깊어질수록 Al - F 결합에 의한 $Al_{2p}$ peak 강도가 감소하고 금속 알루미늄 결합에 의한 $Al_{2p}$ peak 강도가 증가하였다. 입자의 충돌에 의해서 표면원자들이 mixing 됨으로써 알루미늄의 표면에 50~100 $\AA$ 정도의 두께를 가진 $AlF_x$ 층이 형성되는 것으로 분석되었다. 같은 조건에서 반응성 이온식각된 알루미늄 산화막의 경우에는 mixing 효과가 알루미늄보다 작으므로 상대적으로 얕은 범위(10~20 $\AA$)에서 F가 O를 치환하여 $AlF_x$층이 형성되었다.

• 한국분무공학회지
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• 제8권1호
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• pp.16-22
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• 2003

Zeta potential measurements of colloid particles suspended in a liquid are performed by a Zeta Meter developed. There are many applications of colloid stability in spray technology, paints, wastewater treatment, and pharmaceuticalse. Zeta potentials of charged particles are obtained by measuring the electrophoretic velocities of the particles using video enhanced microscopy and image analysis program. The values of zeta potential of polystyrene latex(PSL), $silica(SiO_2)$M, polyvinylidence difluoride(PVDF), silicon nitride, and alumina particles in deionized (DI) water were measured to be -40.5, -31.9, -25.2, -15.1 and -10.1mV, respectively. The particles having high zeta potential less than -20 mV are stable in DI water, because the double layers of them have strong repulsive forces mutually, and the particles having low zeta potential over -20mV are unstable due to Van Der Waals forces. Silica(>20nm), PSL, aluminum and PVDF particles were found to be stable that would remain separate and well disperse, while silicon nitride and alumina particles were found to be unstable that would gradually agglomerate in DI water.

• 한국주조공학회지
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• 제12권4호
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• pp.335-345
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• 1992

Aluminum alloy matrix composites reinforced with various amounts of SiC particles have been produced by rheo-compocasting followed by hot extrusion. A relatively uniform distribution of SiC particles in the composites was obtained. The amounts of pore and SiC particles cluster were relatively small in the composites. Particle free zones were observed in the hot extruded composites when the amount of SiC particles was less than 20 vol%. However, the width of particle free zone decreases with the increase of SiC particle content. Eutectic Si phase play an important role for improving bonding between SiC particle and matrix. Tensile and yield strength increased with the increase of SiC particle content. the strenthening effect of SiC particle addition was effective even at relatively high temperature of 573 K.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.1079-1082
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• 2004

Dense $BaMgAl_{10}O_{17}:Eu^{2+}$ phosphor particles with a spherical shape have been synthesized through spray pyrolysis method using basic aluminum nitrate precursor as a spray solution. Also, a thin layer of silica on the surface of $BaMgAl_{10}O_{17}:Eu^{2+}$ particles were coated by hydrolysis reaction of alkoxide sources with the particles. The correlation between PL intensity and surface treatment by coating for the dense $BaMgAl_{10}O_{17}:Eu^{2+}$ particles have been investigated.

• 정보저장시스템학회:학술대회논문집
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• 정보저장시스템학회 2005년도 추계학술대회 논문집
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• pp.179-183
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• 2005

Particles in the HDD can cause serious damages such as scratches and thermal asperity(TA) at the head/disk interface(HDI). Accordingly, particles cause data loss including physical and electrical damages. To improve the reliability of head-disk interface, understanding the damage characteristics at the HDI due to particle interactions is required. The materials such as $A1_2O_3$, TiC and aluminum were used in this experiment. The size and hardness of particles injected into the HDI are closely relevant to surface damage caused the data loss on the disk and head. In this paper, a variety of scratches were analyzed using scanning electron microscope(SEM) and atomic force microscope(AFM). In order to analyze defects of very small size on the disk, optical surface analyzer(OSA) was also used.